let d1=new Date();
let d2=new Date('2021/08/10 12:00:00');
let time=d2.getTime()-d1.getTime();
let shi=parseInt(time/1000/60/60);
let feng=parseInt((time/1000/60)%60);
let miao=parseInt((time/1000)%60);
let span=document.querySelectorAll('.shi1')
span[0].innerHTML=shi;
span[1].innerHTML=feng;
span[2].innerHTML=miao;

setInterval(function(){
    let d1=new Date();
let d2=new Date('2021/08/10 12:00:00');
let time=d2.getTime()-d1.getTime();
let shi=parseInt(time/1000/60/60);
let feng=parseInt((time/1000/60)%60);
let miao=parseInt((time/1000)%60);
let span=document.querySelectorAll('.shi1')
if(shi<10){
    span[0].innerHTML='0'+shi;
}else{
    span[0].innerHTML=shi;
}
if(feng<10){
    span[1].innerHTML='0'+feng;
}else{
    span[1].innerHTML=feng;
}
if(miao<10){
    span[2].innerHTML='0'+miao;
}else{
    span[2].innerHTML=miao;
}

},1000)